Automated vacuum port

ABSTRACT

An evacuable chamber having two coaxial ports and a roughing port permits a user to insert a probe into a vacuum system without bringing the vacuum system to atmospheric pressure. When the probe is inserted into the first coaxial port it actuates a valve on the roughing port to connect the chamber with a vacuum roughing pump. A vacuum tight seal is also formed between the probe and the first coaxial port when the probe is inserted. Further insertion of the probe is prevented by a stop until the chamber is evacuated. The stop is released, and a valve between the chamber and the second coaxial port is opened upon evacuation of the chamber. The probe can then be inserted into the vacuum system connected to the second coaxial port. When the probe is removed, the valve on the second coaxial port is closed by a spring, and then the valve on the roughing port is closed by a spring. When the probe is removed from the first coaxial port, the chamber returns to atmospheric pressure, which aids in closing both valves tightly.

Kruger 1 Oct. 24, 1972 [54] AUTOMATED VACUUM PORT [72] Inventor: WilliamP. Kruger, Los Altos Hills,

Calif.

[73] Assignee: Hewlett-Packard Company, Palo Alto, Calif.

22 Filed: June 22,1971

21 Appl.No.: 155,446

[52] U.S. Cl. ..l37/320 Primary ExaminerM. Cary Nelson AssistantExaminerDavid R. Matthews Att0rneyRoland l. Griffin [57] ABSTRACT Anevacuable chamber having two coaxial ports and a roughing port permits"a user to insert 'a probe .into a vacuum system without bringing thevacuum system to atmospheric pressure. When the probe is inserted intothe first coaxial port it actuates a valve on the roughing port toconnect the chamber with a vacuum roughing pump. A vacuum tight seal isalso formed between the probe and the first coaxial port when the probeis inserted. Further insertion of the probe is prevented by a stop untilthe chamber is evacuated. The stop is released, and a valve between thechamber and the second coaxial port is opened upon evacuation of thechamber. The probe can then be inserted into the vacuum system connectedto the second coaxial port. When the probe is removed, the valve on thesecond coaxial port is closed by a spring, and then the valve on theroughing port is closed by a spring, When the probe is removed from thefirst coaxial port, the chamber returns to atmospheric pressure, whichaids in closing both valves tightly.

5 Claims, 1 Drawing Figure PATENTEDHBT M 1972 3.699; 997

lNVENTOR WILLIAM R KRUGER AUTOMATED VACUUM PORT BACKGROUND AND SUMMARYOF T INVENTION unsuitable for some operations during which the.

vacuum chamber must remain evacuated. The second method, while itovercomes some of the limitations of the first method, is extremelyexpensive. These limitations of the first two methods can be overcome bythe third. However, the third method is usually susceptible to humanerror since the valves must be operated in the proper sequence to avoidcontaminating the vacuum system.

The present invention is an improved version of the third method. Theappropriate valves open and close automatically in response to insertionor removal of a probe containing the material or instrument to betransferred to the vacuum system. The automatic operation of theapparatus minimizes the opportunity for human error and consequentvacuum system malfunction while it shortens significantly the timerequired to transfer material or instruments into orout of the vacuumsystem.

The automated vacuum port apparatus comprises an evacuable chamber withthree ports attached to it. The first and second ports are coaxial andat opposite ends of the chamber so that the probe can be insertedthrough the chamber into the vacuum system. The third port is connectedto a roughing pump. When the probe is inserted through the first port,it actuates a mechanism which opens a door-like valve on the third portto evacuate the chamber. Further insertion of the probe is prevented bya stop until the pressure in the chamber reachesa predetermined level.When the predetermined pressure is reached, further insertion of I theprobe actuates a mechanism which opens another door-like valve on thesecond port and permits the probe to pass into the vacuum system.

When the probe is withdrawn from the vacuum system the sequence ofevents is reversed. After the probe is withdrawn from the second portthe valve on that port closes. Similarly, as the probe is withdrawn tothe first port the valve on the third port closes. When the probe iscompletely withdrawn, the chamber returns to atmospheric pressure; andthis pressure helps close both valves tightly.

DESCRIPTION OF THE DRAWINGS The drawing shows a crosssectional plan viewof the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawing achamber is formed by a bottom plate 12 and a housing 14 with a seal 11between them. Coaxial ports 16 and 18 are situated in opposite sides ofhousing 14 about axis 15. A port 20, situated in the top of housing 14,is connected to a "vacuum roughing pump (not shown). Port 18 is attachedto a vacuum system 22. A probe 24 is shown inserted into port 16; anO-ring 26 in a groove 28 forms a vacuum tight seal between port 16 andprobe 24. Probe 24 may be used for transferring many different materialsor instruments into vacuum system 22, such as solid, liquid, or gaseoussamples; arnpoules; photographic plates; radioactive materials; andionization chambers.

As probe 24 is moved toward the left, it engages inclined surface 30 oflever 32, rotating the lever as shown by arrow 34. As the lever isrotated, an elastomer seal 36, attached to lever 32, is pulled away fromport 20. The elastomer seal and lever comprise a valve 37, and thisopening of valve 37 allows the roughing pump to evacuate chamber 10.Further insertion of the probe is prevented by a lever 38, which acts asa stop and is attached to a swivel plate 42 through a bell crank 40. Aplate 44 with a captive O-ring 46 is loosely attached to swivel plate 42by spools 48. Swivel plate 42 in turn is attached to bottom plate 12 atpivot 52; and bell crank 40, to the swivel plate at pivot 54. The swivelplate thus acts with a high mechanical advantage on lever 38. Elements42, 44, 46, and 48 comprise a valve 50 and the seating pressure on valve50,

' provided by the pressure in chamber 10 and a spring 56, keeps lever 38upright.

When the pressure in chamber 10 drops to approximately thepressure inport 18, the seating force on valve 50 is reduced to the force of spring56. That force is low enough to allow probe 24 to rotate lever 38, asshown by arrow 58, while the probe is inserted further into chamber 10.As lever 38 rotates it opens valve 50,

as shown by arrow 60, which allows probe 24 to pass through port 18'int0vacuum system 22. A groove 62 in port 18 containing an O-ring 64 makes aseal with probe 24, greatly reducing diffusion of air from chamber 10into vacuum system 22. Once the probe has been inserted into vacuumsystem 22, the probe can be left in there for an indefinite period oftime.

Upon removal of probe 24 from vacuum system 22, valve 50 will be closedby spring 56 when the end of the probe moves past lever 38. The loosemounting of plate 44 on spools 48 allows O-ring'46 to seat squarelyagainst the end of port 18 even with the low seating force applied byspring 56. When probe 24 clears lever 32, a spring 66 closes valve 37,disconnecting the roughing pump from chamber 10. Air will then fillchamber 10 as the probe is moved past O-ring 26, and the air pressurewill'aid springs 56 and 66 in closing valves 50 and 37 securely.

There are other means which could be used to restrain the insertion ofprobe 24, before it contacts lever 38, while chamber 10 is beingevacuated. For example an electrical pressure sensing device inside thebox could be connected to a solenoid-actuated stop, or

.a mechanical pressure sensing device, such as an simple since they areall attached to the removable bottom plate 12. Iclaim:

l. A vacuum port apparatus comprising:

an evacuable chamber;

a first and a second port on the chamber for receiving a probe, thefirst and second ports each having seal means for making a vacuum tightseal with the probe;

a roughing port on the chamber connected to a vacuum pump;

first valve means for opening a passage between the chamber and theroughing port for evacuating the chamber in response to insertion of theprobe through the first port;

stop means for inhibiting further insertion of the probe into thechamber until the pressure in the chamber reaches a predetermined value;and

second valve means for opening apassage between the chamber and secondport in response to further insertion of the probe after the chamberreaches the predetermined pressure to permit the probe to pass throughthe second port.

2. A vacuum port apparatus as in claim 1 wherein:

the second valve means closes the passage between the chamber and thesecond port in response to withdrawal of the probe from the chamber; and

the first valve means closes the passage between the chamber and theroughing port in response to withdrawal of the probe from the firstport.

3. A vacuum port apparatus as in claim 2 wherein the first valve meanscomprises:

a lever mounted on a pivot within the chamber;

a seal attached to a first end of the lever; and

a spring attached to a second end of the lever and to a fixed portion ofthe chamber to force the seal against the roughing port for closing thepassage between the chamber and the roughing port;

whereby the probe, when inserted through the first port, engages thesecond end of the lever to pivot the lever, forcing the seal away fromthe roughing port.

4. A vacuum port apparatus as in claim 2 wherein the second valve meanscomprises:

a swivel plate pivoted within the chamber;

a seal attached to the swivel plate;

a spring attached to the swivel plate and to another fixed portion ofthe chamber to force the seal against the second port for closing thepassage between the chamber and the second port;

a lever pivoted within the chamber; and

a bell crank attached to a first end of the lever and the the swivelplate;

whereby the probe, when it is inserted into the chamber, engages thelever to pull the swivel plate and the seal away from the second port,opening a passage between the chamber and the second port.

5. A vacuum port apparatus as in claim 4 wherein the stop meanscomprises the second valve means.

1. A vacuum port apparatus comprising: an evacuable chamber; a first anda second port on the chamber for receiving a probe, the first and secondports each having Seal means for making a vacuum tight seal with theprobe; a roughing port on the chamber connected to a vacuum pump; firstvalve means for opening a passage between the chamber and the roughingport for evacuating the chamber in response to insertion of the probethrough the first port; stop means for inhibiting further insertion ofthe probe into the chamber until the pressure in the chamber reaches apredetermined value; and second valve means for opening a passagebetween the chamber and second port in response to further insertion ofthe probe after the chamber reaches the predetermined pressure to permitthe probe to pass through the second port.
 2. A vacuum port apparatus asin claim 1 wherein: the second valve means closes the passage betweenthe chamber and the second port in response to withdrawal of the probefrom the chamber; and the first valve means closes the passage betweenthe chamber and the roughing port in response to withdrawal of the probefrom the first port.
 3. A vacuum port apparatus as in claim 2 whereinthe first valve means comprises: a lever mounted on a pivot within thechamber; a seal attached to a first end of the lever; and a springattached to a second end of the lever and to a fixed portion of thechamber to force the seal against the roughing port for closing thepassage between the chamber and the roughing port; whereby the probe,when inserted through the first port, engages the second end of thelever to pivot the lever, forcing the seal away from the roughing port.4. A vacuum port apparatus as in claim 2 wherein the second valve meanscomprises: a swivel plate pivoted within the chamber; a seal attached tothe swivel plate; a spring attached to the swivel plate and to anotherfixed portion of the chamber to force the seal against the second portfor closing the passage between the chamber and the second port; a leverpivoted within the chamber; and a bell crank attached to a first end ofthe lever and the the swivel plate; whereby the probe, when it isinserted into the chamber, engages the lever to pull the swivel plateand the seal away from the second port, opening a passage between thechamber and the second port.
 5. A vacuum port apparatus as in claim 4wherein the stop means comprises the second valve means.